As previously discussed, Dave Allen's reworking the NPIV patches to
do creation/deleation of vports via the node device APIs. Thus, this

patch adds the 2 new APIs required for this approach.

I would really prefer to see this API in 0.6.3, even if there
is no backend implementation, this should ease our work and also
allow other people with distinct node storage implementation to
provide patches for this too. For this reason I would prefer to see
the API go in as earlier as possible in an official release to
allow people to work on those as needed.

For my part, I'm ok with having the API in 0.6.3, as it is not going to
change as I work on the backend implementation.